This invention relates to laboratory apparatus for the automated measuring of the volume of liquid in sample containers arranged in sets, such as sample tubes in tube racks and sample wells in well trays. In particular, the apparatus utilizes an ultrasonic sensor to detect the height of liquid in a tube cavity or well cavity and determine the volume from an algorithm that calculates the volume from the shape of the cavity and the height of the liquid surface from the bottom of the cavity. The automated measuring apparatus includes optional auxiliary sensors, such as a camera, to visually inspect and record the status of a cavity or the identity of a sample or samples from a marking adjacent the cavity or on a surface covering the cavity.
A primary object of this invention is to create an automated measuring device for a variety of laboratory containers for the purpose of quality assurance, sample management and other purposes.
The method of this invention is to take the automated measurement of the volume of various laboratory racks and plates or other grouped containers by use of an ultrasonic transducer being passed over the associated cavity position to measure the height of matter in the cavity which would then be interpolated to indicate the volume of the material in the particular cavity.
While typical laboratory racks and plates or other sets of grouped containers are frequently positioned based on standard spacing, there is no requirement that they be so spaced for the automated measuring system of this invention. Many standard plates and racks are based on a matrix of 98 or 384 wells or tubes. Non standard or random spacing could be addressed by the invented device as well by appropriate programming.
This device would provide an accurate method of collecting interpolated volume data in a rapid fashion.
Other methods currently in use to establish volumes and or weights of tubes or racks containing tubes or containers are to weigh each associated tube or container. Assuming that the tube had been previously tare weighted, the weight of the contents could be determined. However, with laboratory well plates or trays there is no easy solution. The wells are customarily formed as part of the plate and do not have removable containers. As such, individual cavities cannot be removed to be measured for volume or weight. The automated measuring device of this invention solves this problem by measuring the liquid level in the cavity.